Network Service Providers (NSPs) provide multimedia services to subscribers via subscriber devices and routers of service provider networks maintained by the NSPs. Routers of service provider networks operate within the third layer, i.e., the network layer, of the Open Systems Interconnection (OSI) reference model, and typically communicate with each other using layer three protocols. As a result, routers are often referred to as network layer devices or layer three devices. Similarly, the functionality provided by routers that facilitates provision of Internet services is often referred to as network layer functionality. The routers maintained by NSPs and used by NSPs to provide multimedia services may be referred to as Service Edge (SE) routers. NSPs may use SE routers to provide multimedia services that are differentiated on a per-subscriber basis. Enterprise administrators provide similar services in the context of an enterprise network, such as business campus network or a university campus network.
For example, an NSP or enterprise administrator may allow subscribers to receive multicast streams on associated, respective subscriber devices, also referred to as customer premises equipment (CPE). In order to allow a subscriber device to receive multicast streams, SE routers process requests for the multicast streams, e.g., Internet Group Management Protocol (IGMP) host membership reports, issued by the subscriber device. To provide requested multicast streams, the SE routers or a downstream layer two network device typically replicates and forwards packets of a multicast stream for each subscriber device that has requested the multicast stream. Replication of multicast streams on a per-subscriber basis consumes significant processing and memory resources of the routers, as well as bandwidth on the outbound network links from the routers.
In one traffic delivery model, an NSP or enterprise administrator establishes one or more access nodes between the subscriber devices and the SE routers to aggregate upstream network traffic from multiple subscriber devices and disaggregate downstream network traffic to the subscriber devices. For example, multiple subscriber devices may connect to an SE router via a multiservice access node (MSAN), e.g., a digital subscriber line access multiplexer (DSLAM) or an Ethernet switch, maintained by the NSP or enterprise administrator. Although data for the multiple subscriber devices connected to the switch are transported over the same physical connection between the MSAN and the SE router, each of the subscriber devices has a dedicated subscriber interface, i.e., virtual connection, to the router and hence the Internet.
In addition, the NSP or enterprise administrator may establish respective customer-specific Virtual Local Area Networks (VLANs), or CVLANs, between subscriber devices and SE routers to transport unicast traffic to individual subscribers, as well as a multicast VLAN, or MVLAN, to transport multicast traffic to all subscribers. To receive multicast traffic associated with a multicast group, e.g., an Internet Protocol television (IPTV) channel, a subscriber device issues a membership request, e.g., an Internet Group Management Protocol (IGMP) multicast group membership request, for the multicast group on its respective CVLAN to the SE router. The MSAN, which is positioned between the subscriber device and the SE router, forwards the request to the SE router on the CVLAN for the subscriber device. In addition to forwarding the membership request, the MSAN snoops the content of the membership request as it is communicated to the SE router and determines the particular multicast group requested by the subscriber device, and maps the multicast group to a CVLAN interface for the subscriber device. Thereafter, as the MSAN receives multicast traffic from the SE router on the MVLAN, the MSAN locally elaborates multicast traffic for the multicast group to the customer-facing CVLAN interfaces for output to the subscriber devices. In this way, the MSAN elaborates individual multicast streams only to CVLANs for subscriber devices that have requested the multicast streams.
In such system, the intermediate MSAN typically has no information as to which multicast groups a subscriber device is permitted to request and ultimately receive. As such, some system have utilized admission control signaling protocols by which the SE router signals the MSAN as to which groups may be provisioned to each subscriber devices and, therefore, which subscriber-originated requests should be snooped and processed. For example, conventional techniques for performing admission control signaling involve implementing an access node configuration protocol, such as the Access Node Control Protocol (ANCP) or Layer Two Control Protocol (L2CP). Execution of these additional signaling protocols on the devices, however, adds significant complexity to the access node or subscriber devices.